A new Ebola outbreak in the Democratic Republic of the Congo (DRC) is unrelated to the 6-month-old epidemic in West Africa, a genetic analysis has confirmed. Although the virus belongs to the same species, Ebola-Zaire, the strain is genetically so different that it "is definitely not a dissemination of the outbreak in West Africa,” says virologist Eric Leroy of the International Centre for Medical Research of Franceville, the World Health Organization (WHO) collaborating center in Gabon that is characterizing the DRC virus.

Meanwhile, WHO and Doctors Without Borders (MSF) today issued fresh and even more urgent calls for immediate, massive international action to contain the West African outbreak, which is spiraling out of control. At a U.N. briefing today, MSF's Joanne Liu painted a particularly desperate picture of the situation on the ground.

"Ebola treatment centers are reduced to places where people go to die alone, where little more than palliative care is offered," Liu said. "It is impossible to keep up with the sheer number of infected people pouring into facilities. In Sierra Leone, infectious bodies are rotting in the streets. Rather than building new Ebola care centers in Liberia, we are forced to build crematoria."

At the same briefing, WHO Director-General Margaret Chan raised her fist and called for "Action, action, action!"

The DRC outbreak, first reported to WHO on 26 August, has so far sickened 53 people and killed 31, according to WHO. Early test results suggested the two outbreaks were caused by two different species of Ebola. (There are five species of Ebola virus, three of which cause outbreaks in humans: Zaire, Sudan, and Bundibugyo.) But the DRC outbreak, like the one in West Africa, turned out to be Zaire, Leroy wrote to ScienceInsider in an e-mail over the weekend.

Now, a sequence of 346 base pairs of one of the virus's genes has shown that the two outbreaks aren't directly related. The fragment has seven mutations compared with genomes from the current outbreak in Guinea, but only four mutations compared with the strain that caused the first known Ebola outbreak in 1976, also in the DRC, which was then named Zaire. It is even more closely related—by just three mutations—to the strain that caused an outbreak in the DRC city of Kikwit in 1995. Leroy says he hopes to have a full genome sequence of the new DRC strain by the end of this week.

An epidemiological investigation hadn't suggested any links between the two outbreaks either. The index case in the DRC is believed to have been a pregnant woman from Ikanamongo Village in the north of the country, who prepared bushmeat hunted by her husband.

The outbreak zone in the DRC is in a remote area approximately 1200 kilometers north of Kinshasa. "Motorcycles, canoes, and satellite phones have been supplied to facilitate outbreak investigation and contact tracing,” a statement issued today by WHO noted. "A dedicated helicopter will be made available soon.”

That remoteness makes the response more difficult—but it's also reason to be confident that this outbreak can be contained, Leroy says, because infected people won't travel as much as they do in West Africa. In addition, he says, "the DRC has much experience with Ebola outbreaks, so all the people know very well what to do to stop the outbreak.”

Public health experts are sounding increasingly alarmed. "There is a window of opportunity to tamp this down, but that window is closing. We need action now to scale up the response," said Tom Frieden, the director of the Centers for Disease Control and Prevention in Atlanta, today at a press conference after returning from a visit to affected countries in West Africa.

“In some ways, the most upsetting thing I saw is what I didn’t see," Frieden said. "I didn’t see enough beds for treatment. So in one facility which had just opened with 35 beds, there were 63 patients, many of them lying on the ground. I didn’t see data coming in from large parts of the country where Ebola might be spreading. I didn’t see the kind of rapid response team that’s needed to stop a single cluster from becoming a large outbreak."

At the U.N. briefing, MSF's Liu sharply criticized the international reaction to the outbreak so far, as MSF has done before. "The response has been too little, too late," she says. Liu also criticized the fact that WHO didn't declare the outbreak a Public Health Emergency of International Concern (PHEIC) until 8 August. "We have lost 6 months," she said.

At a press conference later, Chan acknowledged that WHO and other organizations realized too late just how serious the outbreak would become. "I think it is fair to say that all organizations involved in this underestimated the complexity and the magnitude" of the outbreak, she said. But Chan defended the timing of the PHEIC declaration, which was triggered by the appearance of Ebola in Nigeria. "I think it was the right time to call it," she said.